Imaging system for detecting defects of lenticular grating glass substrate and control method

Abstract

The invention discloses an imaging system for detecting defects of a lenticular grating glass substrate and a control method. Comprising a light source, a three-axis motion module, a detected lenticular grating glass substrate, an image acquisition module, an image calculation module and a multi-path coupling control module, the light source is arranged on the three-axis motion module; the light source is used for irradiating the detected lenticular grating glass substrate; the image acquisition module is used for acquiring light reflected by the detected lenticular grating glass substrate to obtain a self-coherence grating image and sending the self-coherence grating image to the image calculation module; the image calculation module is used for calculating the definition and the stripe straightness of the self-coherent grating image and sending the definition and the stripe straightness to the multi-path coupling control module; and the multi-path coupling control module is used for controlling the movement of the three-axis movement module according to the definition and the stripe straightness so as to adjust the pose of the light source. And the self-coherent grating image for detecting the defects of the lenticular grating glass substrate can be effectively obtained.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of machine vision technology, and in particular to an imaging system and a control method for detecting defects of a cylindrical grating glass substrate. Background Art

[0002] Since the observer does not need to wear special glasses or other auxiliary tools, naked-eye 3D display screens have a huge demand in advertising, media, demonstrations and exhibitions. With the further development of its technology, it can be gradually applied in personal daily display scenarios such as mobile phones, tablets and cars. Among them, 3D display based on cylindrical grating is the mainstream technology in the current 3D display field due to its strong practicality, easy processing and high brightness, and cylindrical grating glass substrate is the most core component.

[0003] During the production and processing of cylindrical grating glass substrates, foreign matter, bubbles, bumps, scratches and other defective products may be produced. Defect detection is an essential key process in the production and processing process. However, due to the special optical structure of cylindrical grating glass substrates, ordinary imaging methods of machine vision, whether line scanning or area array, are very difficult. The light path is refracted and reflected by the cylindrical lens of the substrate and is severely distorted. The angle of the real defect varies greatly and is not easy to capture. The background texture is complex and changes with the machine model. The optical detection layout suitable for a certain machine model may be completely ineffective for another machine model. Defects can be detected by using a microscope for microscopic local inspection and the optical path is relatively stable, but its field of view is very small. Using this method to perform global inspection of glass substrates will make the system extremely complex and costly. Summary of the invention

[0004] The embodiment of the present invention provides an imaging system and a control method for detecting defects of a lenticular lens grating glass substrate, which can effectively obtain a self-coherent grating image for detecting defects of a lenticular lens grating glass substrate.

[0005] In a first aspect, an embodiment of the present invention provides an imaging system for detecting defects of a cylindrical grating glass substrate, comprising: a light source, a three-axis motion module, a cylindrical grating glass substrate to be tested, an image acquisition module, an image calculation module, and a multi-channel coupling control module;

[0006] The light source is a surface light source with a plurality of evenly arranged irregular strip lens columns; the light source is arranged on the three-axis motion module; the light source and the image acquisition module are located on the measured cylindrical lens grating glass substrate; the image acquisition module is connected to the image calculation module, the image calculation module is connected to the multi-way coupling control module, and the multi-way coupling control module is connected to the three-axis motion module;

[0007] The light source is used to illuminate the measured cylindrical lens grating glass substrate; the image acquisition module is used to collect the light reflected by the measured cylindrical lens grating glass substrate to obtain a self-coherent grating image, and send the self-coherent grating image to the image calculation module; the image calculation module is used to calculate the clarity and stripe straightness of the self-coherent grating image, and send the clarity and stripe straightness to the multi-channel coupling control module; the multi-channel coupling control module is used to control the movement of the three-axis motion module according to the clarity and the stripe straightness to adjust the posture of the light source.

[0008] In a second aspect, an embodiment of the present invention further provides a control method for an imaging system for detecting defects of a lenticular lens grating glass substrate, the method being used in the imaging system for detecting defects of a lenticular lens grating glass substrate in this embodiment, comprising:

[0009] Acquire a self-correlated grating image; wherein the self-correlated grating image is obtained by collecting light reflected by the measured cylindrical mirror grating glass substrate;

[0010] Determining the clarity and stripe straightness of the autocorrelation grating image, and judging whether the clarity and stripe straightness meet preset conditions;

[0011] If the clarity and / or stripe straightness do not meet the preset conditions, the position of the light source is adjusted according to the clarity and / or the stripe straightness, and the operation of obtaining the self-coherent grating image is returned to be executed until the clarity and stripe straightness meet the preset conditions; wherein the light source is used to illuminate the measured cylindrical mirror grating glass substrate.

[0012] The embodiment of the present invention provides an imaging system for detecting defects of a cylindrical grating glass substrate and a control method thereof. The system comprises: a light source, a three-axis motion module, a cylindrical mirror grating glass substrate to be measured, an image acquisition module, an image calculation module and a multi-channel coupling control module; wherein the light source is attached with a surface light source having a plurality of evenly arranged special-shaped strip lens columns; the light source is arranged on the three-axis motion module; the light source and the image acquisition module are located on the cylindrical mirror grating glass substrate to be measured; the image acquisition module is connected to the image calculation module, the image calculation module is connected to the multi-channel coupling control module, and the multi-channel coupling control module is connected to the three-axis motion module; the light source is used to irradiate the cylindrical mirror grating glass substrate to be measured; the image acquisition module is used to collect light reflected by the cylindrical mirror grating glass substrate to be measured to obtain a self-coherent grating image, and send the self-coherent grating image to the image calculation module; the image calculation module is used to calculate the clarity and stripe straightness of the self-coherent grating image, and send the clarity and stripe straightness to the multi-channel coupling control module; the multi-channel coupling control module is used to control the movement of the three-axis motion module according to the clarity and stripe straightness to adjust the position and posture of the light source. The imaging system for detecting defects of a lenticular grating glass substrate provided by an embodiment of the present invention can effectively obtain a self-coherent grating image for detecting defects of a lenticular grating glass substrate by adjusting the position of the light source according to the clarity and stripe straightness of the self-coherent grating image until the clarity and stripe straightness of the acquired self-coherent grating image meet the defect detection conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of an imaging system for detecting defects of a cylindrical grating glass substrate in Embodiment 1 of the present invention;

[0014] Figure 2 This is an example diagram of an anisotropic strip lens column in the first embodiment of the present invention;

[0015] Figure 3 It is a cross-sectional view of a surface light source attached with a plurality of special-shaped strip lens columns in the first embodiment of the present invention;

[0016] Figure 4 This is a motion example diagram of a three-axis motion module in the first embodiment of the present invention;

[0017] Figure 5 is a principle block diagram of an imaging system for detecting defects of a cylindrical grating glass substrate in an embodiment of the present invention;

[0018] Figure 6 It is a flow chart of an imaging method for detecting defects of a cylindrical grating glass substrate in Embodiment 2 of the present invention;

[0019] Figure 7 It is a schematic diagram of a self-correlated grating image in the second embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0021] Embodiment 1

[0022] Figure 1 A schematic diagram of the structure of an imaging system for detecting defects of a cylindrical grating glass substrate provided in the first embodiment of the present invention is shown in FIG. Figure 1 As shown, the system includes: a light source 11, a three-axis motion module 12, a cylindrical lens grating glass substrate 13 to be measured, an image acquisition module 14, an image calculation module 15 and a multi-channel coupling control module 16.

[0023] Among them, the light source 11 is attached with a surface light source of multiple uniformly arranged special-shaped strip lens columns; the light source is set on the three-axis motion module; the light source and the image acquisition module are located on the measured cylindrical lens grating glass substrate. The image acquisition module 14 is connected to the image calculation module 15, the image calculation module 15 is connected to the multi-way coupling control module 16, and the multi-way coupling control module 16 is connected to the three-axis motion module 12.

[0024] Among them, the uniform arrangement of the irregular strip lens columns can be understood as the spacing between two adjacent irregular strip lens columns on the surface light source is equal. The end face of the irregular strip lens column is irregular. The irregular shape can be understood as irregular shape. For example, Figure 2 is an example diagram of an anisotropic strip lens column in this embodiment, such as Figure 2 As shown, the end face of the strip lens column is irregular, that is, the figure has at least one side that is a curve. In this embodiment, the maximum radius envelope of the irregular strip lens column matches the size of the cylindrical grating in the cylindrical grating glass substrate to be measured, that is, the difference between the maximum radius envelope of the irregular strip lens column and the size of the cylindrical grating in the cylindrical grating glass substrate to be measured is within a preset range, and the length of the irregular strip lens column is determined according to the size of the camera field of view, such as being set to between 200-300 mm. In this way, the cylindrical grating glass substrate can be imaged normally.

[0025] In this embodiment, after designing the special-shaped strip lens column, a plurality of special-shaped strip lens columns are attached to a surface light source with uniform light emission and surface cleaning treatment according to the process requirements, and the portion of the surface light source to which the special-shaped strip lens column is not attached is subjected to light shielding treatment, so that the light source has a periodic grating characteristic. That is, the spatial distribution frequency domain characteristics of the special-shaped strip lens column in the light source and the spatial distribution frequency domain characteristics of the cylindrical grating in the cylindrical grating glass substrate to be measured are in a specific proportional relationship. Among them, the proportional relationship can be a value between 0.5-1.2. For example, Figure 3 is a cross-sectional view of a surface light source attached with a plurality of special-shaped strip lens columns in this embodiment, such as Figure 3 As shown, the surface light source is attached with evenly arranged special-shaped strip lens columns, and the portion without special-shaped strip lens columns is shielded. In this embodiment, the optical properties of the cylindrical mirror grating glass substrate to be tested are utilized, and the above-mentioned light source with periodic grating characteristics is used to illuminate the cylindrical mirror grating glass substrate to be tested to excite and obtain a self-coherent grating image for defect detection. The light and dark alternating self-coherent grating image generated by the system can be effectively used for defect detection, and has the advantages of stable background, clear and stable imaging of defects (including weak defects), and compatibility with different models. It effectively overcomes the disadvantages of other imaging methods such as complex and changeable background, many angles required for defect imaging, and large differences in machine types. In addition, another important advantage of the self-correlation grating image generated by the system is that it can shield most of the surface dust (non-real defects) except for individual large hairs and foreign objects, while the general imaging method will cause weak dust to be imaged, and the characteristics cannot be effectively distinguished from real defects. Compared with the microscopic inspection method, the optical system achieves the goals of "low cost", "simple and reliable" and "global inspection". In addition, the light source will not produce a grating image on ordinary glass. It is not a conventional grating projection principle. The conventional grating projection principle cannot form an image on cylindrical grating glass.

[0026] The image acquisition module is a camera and an acquisition card. The three-axis motion module can rotate and translate around three axes (X axis, Y axis, Z axis). For example, Figure 4 is a motion example diagram of a three-axis motion module in this embodiment, such as Figure 4 As shown, the adjustable quantities of the three-axis motion module are the rotation degrees around the x-axis. Rotation around the y axis Rotation around the z-axis The light source is arranged on the three-axis motion module, so that the three-axis motion module drives the light source to rotate around three axes and to translate along the x-axis in micro-distance during the motion, thereby adjusting its posture. The multi-way coupling control module is used to control the motion of the three-axis motion module.

[0027] Specifically, the light source is used to illuminate the cylindrical mirror grating glass substrate to be measured; the image acquisition module is used to collect the light reflected by the cylindrical mirror grating glass substrate to be measured to obtain a self-coherent grating image, and send the self-coherent grating image to the image calculation module; the image calculation module is used to calculate the clarity and stripe straightness of the self-coherent grating image, and send the clarity and stripe straightness to the multi-channel coupling control module; the multi-channel coupling control module is used to control the movement of the three-axis motion module according to the clarity and stripe straightness to adjust the position of the light source.

[0028] In this embodiment, the light source adjusts the height and angle according to the arrangement direction of the cylindrical grating to be tested, and a rough autocorrelation grating image can be basically obtained. Due to the sensitivity of the autocorrelation grating imaging to the angle and level, the accuracy of general manual adjustment cannot meet the requirements, and for different models, due to the differences in the grating arrangement, the position of the light source must be readjusted. Therefore, the imaging system for cylindrical grating glass substrate defect detection in this embodiment is a feedback self-adjustment system. Figure 5 is a principle block diagram of an imaging system for detecting defects of a cylindrical grating glass substrate in an embodiment of the present invention, such as Figure 5 As shown, the working principle of the system is as follows: the light source is placed on a motion module with adjustable horizontality and rotation, the clarity and stripe straightness of the self-coherent grating image are used as state quantities, and the rotation adjustment amount of the three-axis motion module is used as the control amount to establish a feedback control system to achieve adaptive adjustment to obtain the best self-coherent grating image. That is, the clarity and / or stripe straightness are used as state quantities, and the multi-channel coupling control module is used to control the position of the light source, so that the light source and the measured cylindrical mirror grating glass substrate generate a self-coherent mechanism and obtain a self-coherent grating image whose clarity and stripe straightness meet the preset conditions.

[0029] In this embodiment, the target quantity of the imaging system is that the clarity and flatness meet the preset conditions. It should be noted that the clarity here excludes the influence of lens focusing factors and simply refers to the clarity of the grating image caused by the autocorrelation process. The factors affecting the clarity are the rotation around the central z-axis, the rotation around the x-axis, and the rotation around the y-axis. Therefore, its independent variable is in is the main variable, which plays a decisive role in the clarity of the autocorrelation process; the factors affecting the straightness of the stripes are the rotation degree around the x-axis and the rotation degree around the y-axis, so its independent variable is

[0030] The image calculation module is used to calculate the clarity and straightness of the currently acquired autocorrelation grating image. The specific calculation method can be found in the subsequent embodiments.

[0031] In this embodiment, the multi-way coupling control module is also used to control the three-axis motion module to rotate along at least one axis to adjust the position of the light source according to the clarity deviation and / or the stripe straightness deviation when the clarity and stripe straightness do not meet the preset conditions.

[0032] Among them, the clarity deviation is the deviation between the clarity of the current self-coherent grating image and the target clarity; the stripe straightness deviation is the deviation between the stripe straightness of the current self-coherent grating image and the upper target stripe straightness. It can be seen from the above embodiments that the control process in this embodiment is a two-way coupling control, the clarity and stripe straightness of the current self-coherent grating image and the target clarity and target stripe straightness are input into the multi-way coupling control module to obtain the clarity deviation ΔD(t) and the stripe straightness deviation ΔS(t), and the multi-way coupling control module generates a control instruction according to the clarity deviation and the stripe straightness deviation (the instruction contains ), and sends a control instruction to the three-axis motion module to control the three-axis motion module to rotate along at least one of the X, Y and Z axes to adjust the position of the light source. After the position of the light source is adjusted, the image acquisition module continues to acquire the self-coherent grating image, and sends the latest acquired self-coherent grating image to the image calculation module. After the image calculation module completes the state calculation, it feeds back to the self-coherent grating image until a self-coherent grating image that meets the requirements is obtained.

[0033] In this embodiment, the multi-channel coupling control module is also used to control the three-axis motion module to translate along a direction perpendicular to the grating in the measured cylindrical grating glass substrate when the clarity and / or stripe straightness meets the preset conditions, so as to drive the light source to translate; correspondingly, the image acquisition module is used to acquire the self-coherent grating image corresponding to the translated light source.

[0034] Specifically, when the imaging system can acquire a self-coherent grating image that meets the preset conditions, the self-coherent grating image acquired by the imaging system meets the requirements. Considering that the best capture range of defects for grating images is the transition section of light and dark stripes, and considering the process accuracy requirements of the customized light source special-shaped strip lens column, in order to cover the entire detection area and avoid blind spots, when the clarity and / or stripe straightness meet the preset conditions, the image acquisition module acquires the self-coherent grating image; the three-axis motion module performs multiple macro translations to drive the light source to perform macro translations, and the self-coherent grating image is acquired after each macro translation of the light source to complete the image acquisition of the current area; the external translation mechanism drives the image acquisition module and the three-axis motion module to translate as a whole to the adjacent area, and repeats the operation of multiple macro translations of the three-axis motion module to drive the light source to perform macro translations, and the self-coherent grating image is acquired after each macro translation of the light source, until the image acquisition of the cylindrical lens grating glass substrate under test is completed.

[0035] The imaging system for detecting defects of a cylindrical mirror grating glass substrate disclosed in the present embodiment comprises: a light source, a three-axis motion module, a cylindrical mirror grating glass substrate to be tested, an image acquisition module, an image calculation module and a multi-way coupling control module; wherein the light source is a surface light source having a plurality of special-shaped strip lens columns attached thereto; the light source is arranged on the three-axis motion module; the light source and the image acquisition module are located on the cylindrical mirror grating glass substrate to be tested; the image acquisition module is connected to the image calculation module, the image calculation module is connected to the multi-way coupling control module, and the multi-way coupling control module is connected to the three-axis motion module; the light source is used to irradiate the cylindrical mirror grating glass substrate to be tested; the image acquisition module is used to collect light reflected by the cylindrical mirror grating glass substrate to be tested to obtain a self-coherent grating image, and send the self-coherent grating image to the image calculation module; the image calculation module is used to calculate the clarity and stripe straightness of the self-coherent grating image, and send the clarity and stripe straightness to the multi-way coupling control module; the multi-way coupling control module is used to control the movement of the three-axis motion module according to the clarity and stripe straightness to adjust the position and posture of the light source. The imaging system for defect detection of a lenticular grating glass substrate provided by an embodiment of the present invention can improve the accuracy and efficiency of defect detection of a lenticular grating glass substrate by adjusting the position of a light source according to the clarity and stripe straightness of a self-coherent grating image until the clarity and stripe straightness of the acquired self-coherent grating image meet defect detection conditions.

[0036] Embodiment 2

[0037] Figure 6 1 is a flowchart of an imaging method for detecting defects of a lenticular lens grating glass substrate provided in the second embodiment of the present invention. The method is used in the imaging system for detecting defects of a lenticular lens grating glass substrate in the above embodiment. Figure 6 As shown, the method comprises the following steps:

[0038] S510, acquiring a self-coherent grating image.

[0039] The autocorrelation grating image is obtained by collecting the light reflected by the cylindrical grating glass substrate to be measured. In this embodiment, in order to form an image on the cylindrical grating glass substrate, the light source is a surface light source to which a plurality of evenly arranged special-shaped strip lens columns are attached, and the number of special-shaped strip lens columns included in the light source is in a set ratio with the cylindrical grating in the cylindrical grating glass substrate to be measured; and the portion of the surface light source to which the special-shaped strip lens columns are not attached is subjected to light shielding treatment. And the special-shaped strip lens columns meet the following conditions: the end face is special-shaped; the maximum radius envelope of the special-shaped strip lens columns matches the size of the cylindrical grating in the cylindrical grating glass substrate to be measured.

[0040] In this embodiment, when the light source irradiates the lenticular grating glass substrate at a height and angle according to the arrangement direction of the lenticular grating, the lenticular grating glass substrate reflects the incident light to form an autocorrelation grating image. In order to accurately detect defects based on the autocorrelation grating image, the clarity and stripe straightness of the autocorrelation grating image need to meet the preset conditions. Therefore, the position of the light source needs to be adjusted to obtain the autocorrelation grating image whose clarity and stripe straightness meet the preset conditions.

[0041] S520, determine the clarity and stripe straightness of the autocorrelation grating image, and determine whether the clarity and stripe straightness meet the preset conditions; if the clarity and / or stripe straightness do not meet the preset conditions, execute S530; if the clarity and / or stripe straightness meet the preset conditions, execute S540.

[0042] The autocorrelation grating image is an image composed of light and dark stripes, so the clarity can be represented by the black and white contrast of the autocorrelation grating image, and the stripe straightness can be represented by the straightness of each bright stripe in the autocorrelation grating image. Figure 7 is a schematic diagram of a self-correlated grating image in this embodiment, such as Figure 7 As shown, the autocorrelation grating image is composed of light and dark stripes. The preset condition may be that the clarity and stripe straightness are greater than a certain value.

[0043] Optionally, the clarity of the autocorrelation grating image can be determined by: dividing the autocorrelation grating image into multiple sub-images; determining the black-white contrast of each sub-image; calculating the mean, variance and maximum of the black-white contrast of the multiple sub-images; and determining the clarity of the autocorrelation grating image based on the mean, variance and maximum of the black-white contrast.

[0044] Wherein, the maximum value includes a maximum value or a minimum value. The way to divide the autocorrelation grating image into multiple sub-images may be to divide the autocorrelation grating image in a grid manner, thereby obtaining multiple sub-images. Exemplarily, the autocorrelation grating image may be divided in an N*N grid manner. The way to determine the black-and-white contrast of each sub-image may be: for each sub-image, obtain the gray value of each pixel in the sub-image; determine the average gray value of the pixel whose gray value is less than the first set threshold as the first average gray value; determine the average gray value of the pixel whose gray value is greater than the second set threshold as the second average gray value; and determine the ratio of the second average gray value to the second average gray value as the black-and-white contrast of the sub-image. Wherein, the first set threshold is less than the second set threshold, for example: the first set threshold is set to 0.3, and the second set threshold is set to 0.7. After determining the black-and-white contrast of each sub-image, determine the mean, variance and maximum of the black-and-white contrast of the multiple sub-images, and finally perform weighted summation on the mean, variance and maximum of the black-and-white contrast to obtain the clarity of the autocorrelation grating image.

[0045] Optionally, the method for determining the straightness of stripes in the autocorrelation grating image may be: cropping the stripes in the autocorrelation grating image to obtain multiple stripe sub-images; extracting the stripe center line of the stripe sub-image used; calculating the distances between multiple pixel points on the stripe edge and the stripe center line, and calculating the variance of the multiple distances as the first variance; calculating multiple widths of the stripes, and calculating the variance of the multiple widths as the second variance; and performing weighted summation of the first variance and the second variance to obtain the straightness of the stripes in the stripe sub-image.

[0046] Wherein, the stripes are bright stripes or dark stripes. In this embodiment, only the bright stripes in the autocorrelation grating image are cropped or only the dark stripes in the autocorrelation grating image are cropped. The distance between the multiple pixel points on the edge of the stripe and the center line can be understood as: the distance between the multiple pixel points on one side of the stripe and the center line of the stripe.

[0047] S530, adjusting the position of the light source according to the clarity and / or stripe straightness, and returning to execute the operation of acquiring the self-coherent grating image until the clarity and stripe straightness meet the preset conditions.

[0048] The light source is used to illuminate the cylindrical mirror grating glass substrate to be measured. The light source is installed on the three-axis motion module, and the position of the light source is adjusted by adjusting the position of the three-axis motion module.

[0049] Optionally, the method of adjusting the position of the light source according to the clarity and / or stripe straightness may be: determining a clarity deviation and a stripe straightness deviation; and adjusting the position of the light source according to the clarity deviation and / or the stripe straightness deviation.

[0050] Among them, the clarity deviation is the deviation between the clarity of the current self-coherent grating image and the target clarity; the stripe straightness deviation is the deviation between the stripe straightness of the current self-coherent grating image and the target stripe straightness. The target clarity can be understood as the clarity that meets the conditions, and the target stripe straightness can be understood as the stripe straightness that meets the conditions. In this embodiment, the process of adjusting the position and posture of the light source according to the clarity deviation and / or the stripe straightness deviation can be: first, according to the clarity deviation and / or the stripe straightness, the rotation of the three axes, i.e., the rotation of the X-axis, the rotation of the Y-axis and the rotation of the Z-axis, is determined, and based on the rotation of the three axes, the three-axis motion module is controlled to rotate around the three axes to drive the light source to rotate around the three axes, thereby adjusting the position and posture of the light source.

[0051] Optionally, the method of adjusting the position and posture of the light source according to the clarity deviation and / or the stripe straightness deviation may be: determining the main control channel of the current control according to the change trend of the clarity deviation and / or the stripe straightness deviation; and adjusting the position and posture of the light source controlled by the main control channel.

[0052] Wherein, the control channel is a definition control channel (around the Z axis) or a flatness control channel (around the X axis and the Y axis). In this embodiment, since the factor affecting the definition is the independent variable and is the main variable, therefore, the light source is mainly controlled to rotate along the Z axis according to the clarity deviation. Since the factors affecting the straightness of the stripes are the independent variables Therefore, the fringe straightness deviation controls the rotation of the light source around the X-axis and the Y-axis.

[0053] In this embodiment, after adjusting the position of the light source, the operation returns to the step of obtaining the autocorrelation grating image; determining the clarity and stripe straightness of the autocorrelation grating image, and judging whether the clarity and stripe straightness meet the preset conditions, until the clarity and stripe straightness meet the preset conditions.

[0054] S540, the image acquisition module acquires the self-coherent grating image; the three-axis motion module performs multiple macro translations to drive the light source to perform macro translations, and acquires the self-coherent grating image after each macro translation of the light source, so as to complete the image acquisition of the current area; the external translation mechanism drives the image acquisition module and the three-axis motion module to translate as a whole to the adjacent area, and repeats the operation of multiple macro translations of the three-axis motion module to drive the light source to perform macro translations, and acquires the self-coherent grating image after each macro translation of the light source, until the image acquisition of the cylindrical grating glass substrate to be tested is completed. Finally, defect detection is performed based on the multiple self-coherent grating images acquired. This improves the accuracy of defect detection.

[0055] The three-axis motion module is repeatedly macro-translated to drive the light source to be macro-translated, which may be that the three-axis motion module is repeatedly macro-translated along the x-axis of the three-axis motion platform.

[0056] The technical solution of this embodiment is to obtain a self-coherent grating image; wherein the self-coherent grating image is obtained by collecting the light reflected by the lenticular grating glass substrate under test; determine the clarity and stripe straightness of the self-coherent grating image, and judge whether the clarity and stripe straightness meet the preset conditions; if the clarity and / or stripe straightness do not meet the preset conditions, adjust the position of the light source according to the clarity and / or stripe straightness, and return to perform the operation of obtaining the self-coherent grating image until the clarity and stripe straightness meet the preset conditions. The efficiency and accuracy of defect detection of lenticular grating glass substrates can be improved.

[0057] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0058] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An imaging system for detecting defects in a cylindrical grating glass substrate, characterized in that: include: Light source, three-axis motion module, measured cylindrical mirror grating glass substrate, image acquisition module, image calculation module and multi-channel coupling control module; Wherein, the light source is a surface light source attached with a plurality of evenly arranged special-shaped strip lens columns; the light source is arranged on the three-axis motion module; the light source and the image acquisition module are located on the measured cylindrical lens grating glass substrate; the image acquisition module is connected to the image calculation module, the image calculation module is connected to the multi-way coupling control module, and the multi-way coupling control module is connected to the three-axis motion module; The light source is used to illuminate the measured lenticular grating glass substrate; the image acquisition module is used to collect the light reflected by the measured lenticular grating glass substrate to obtain a self-coherent grating image, and send the self-coherent grating image to the image calculation module; the image calculation module is used to calculate the clarity and fringe straightness of the self-coherent grating image, and send the clarity and fringe straightness to the multi-channel coupling control module; The multi-channel coupling control module is used to control the movement of the three-axis motion module according to the clarity and the stripe straightness to adjust the position of the light source.

2. The system according to claim 1, characterized in that The end face of the special-shaped strip lens column is special-shaped; the maximum radius envelope of the special-shaped strip lens column matches the size of the cylindrical grating in the cylindrical grating glass substrate to be measured.

3. The system according to claim 1 or 2, characterized in that: The spatial distribution frequency domain characteristics of the special-shaped strip lens columns in the light source and the spatial distribution frequency domain characteristics of the cylindrical grating in the cylindrical grating glass substrate to be measured are in a specific proportional relationship; and the part of the surface light source to which the special-shaped strip lens columns are not attached is subjected to shading treatment so that the light source has a periodic grating characteristic.

4. The system according to claim 1, characterized in that The clarity and / or the fringe straightness are used as state quantities, and a multi-way coupling control module is used to control the light source position, so that the light source and the measured cylindrical grating glass substrate generate a self-coherent mechanism and obtain a self-coherent grating image whose clarity and fringe straightness meet preset conditions.

5. The system according to claim 1, characterized in that When the clarity and the stripe straightness meet the preset conditions, the image acquisition module acquires the self-coherent grating image; the three-axis motion module performs multiple macro translations to drive the light source to perform macro translation, and acquires the self-coherent grating image after each macro translation of the light source, so as to complete the image acquisition of the current area; the external translation mechanism drives the image acquisition module and the three-axis motion module to translate as a whole to the adjacent area, and repeats the operation of performing multiple macro translations of the three-axis motion module to drive the light source to perform macro translation, and acquires the self-coherent grating image after each macro translation of the light source, until the image acquisition of the cylindrical grating glass substrate under test is completed.

6. A control method for an imaging system for detecting defects of a cylindrical grating glass substrate, characterized in that: The method is used in the imaging system for detecting defects of a cylindrical grating glass substrate according to any one of claims 1 to 5, comprising: Acquire a self-correlated grating image; wherein the self-correlated grating image is obtained by collecting light reflected by the measured cylindrical mirror grating glass substrate; Determining the clarity and stripe straightness of the autocorrelation grating image, and judging whether the clarity and stripe straightness meet preset conditions; If the clarity and stripe straightness do not meet the preset conditions, the position of the light source is adjusted according to the clarity and / or the stripe straightness, and the operation of obtaining the self-coherent grating image is returned to be executed until the clarity and stripe straightness meet the preset conditions; wherein the light source is used to illuminate the measured cylindrical mirror grating glass substrate.

7. The method according to claim 6, characterized in that Determining the sharpness of the autocorrelation raster image comprises: dividing the autocorrelation grating image into a plurality of sub-images; Determining the black-white contrast of each of the sub-images; Counting the mean, variance and maximum value of the black-white contrast of the plurality of sub-images; wherein the maximum value includes a maximum value or a minimum value; The clarity of the autocorrelation grating image is determined based on the mean, variance and maximum of the black-white contrast.

8. The method according to claim 6, characterized in that Determining the fringe straightness of the autocorrelation grating image comprises: Cutting the stripes in the autocorrelation grating image to obtain a plurality of stripe sub-images; wherein the stripes are bright stripes or dark stripes; Extract the stripe center line of the used stripe sub-image; Calculate the distances between multiple pixel points on the edge of the stripe and the center line of the stripe, and calculate the variance of the multiple distances as the first variance; Calculate multiple widths of the stripes, and calculate the variance of the multiple widths as the second variance; A weighted sum is performed on the first variance and the second variance to obtain the straightness of the stripes in the stripe sub-image.

9. The method according to claim 6, characterized in that Adjusting the position of the light source according to the clarity and / or the stripe straightness includes: Determine the clarity deviation and the stripe straightness deviation; wherein the clarity deviation is the deviation between the clarity of the current self-coherent grating image and the target clarity of the target setting; the stripe straightness deviation is the deviation between the stripe straightness of the current self-coherent grating image and the target stripe straightness of the target setting; The position and posture of the light source is adjusted according to the clarity deviation and the stripe straightness deviation.

10. The method according to claim 9, characterized in that Adjusting the position and posture of the light source according to the clarity deviation and the stripe straightness deviation includes: Determining the main control channel of the current control according to the change trends of the clarity deviation and the stripe straightness deviation; wherein the control channel is a clarity control channel or a straightness control channel; The position and posture of the light source is adjusted according to the main control channel.

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